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Process of carrying out low-temperature chemical cleaning passivation on thermal power plant boiler by utilizing EDTA (Ethylene Diamine Tetraacetic Acid)

A thermal power plant, low-temperature chemical technology, applied in boiler cleaning equipment, metal material coating process, flushing and other directions, can solve problems such as hidden safety hazards for workers and high energy consumption, reduce cleaning costs, shorten cleaning cycles, and shorten Effect of cleaning cycle and cost

Inactive Publication Date: 2012-04-25
NINGXIA ELECTRIC POWER RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this cleaning temperature, the boiler needs to be ignited and pressurized to complete the cleaning. At the same time, it consumes a lot of energy. Cleaning at high temperature brings great hidden dangers to the safety of the staff.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] When cleaning the subcritical pressure natural circulation boiler of model SG-1166 / 17.47-M892 manufactured by Shanghai Boiler Works Co., Ltd., the specific conditions of the boiler are: the material of the steam drum is BHW35, the material of the water wall is SA-210C, Economizer material is SA-210C. The feed water enters the inlet header of the economizer from the single channel on the left side of the boiler through the check valve and the electric valve, flows through the economizer tube group, the intermediate connecting header and the suspension pipe, and then merges in the outlet header of the economizer. The tank is introduced into the drum from the economizer outlet header through three Φ219×25 drum water supply pipes. The feed water is injected into four Φ558.8×60 large-diameter descending pipe sockets through the water supply distribution pipes arranged along the length of the drum, and the feed water is directly mixed with the boiler water in the descending p...

Embodiment 2

[0028] On the basis of the above-mentioned embodiments, according to factors such as boiler usage conditions, conditions such as temperature in steps B, C, D, and E, alkali cleaning time, pH value, cleaning solution mass percentage concentration, and passivation time are changed. See below for details surface

[0029] Example Step B liquid return temperature Step C liquid return temperature, alkali washing time Step D Step E Example 2 35℃ 55℃, about 5 hours The concentration of EDTA-2Na cleaning solution is 4%, the concentration of corrosion inhibitor is 0.4%, and the return temperature is 80±5℃ The pH value is around 8.5, and the passivation time is less than 5 hours Example 3 45℃ 65℃, about 6 hours The concentration of EDTA-2Na cleaning solution is 6%, the concentration of corrosion inhibitor is 0.5%, and the return temperature is 60±5℃ The pH value is about 9.5, and the passivation time is about 3 hours

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Abstract

The invention relates to a low-temperature chemical cleaning method for a thermal power plant boiler and in particular relate to a process of carrying out low-temperature chemical cleaning passivation by utilizing EDTA (Ethylene Diamine Tetraacetic Acid). The process comprises the following steps: A. connecting a chemical cleaning platform with a system which needs to be cleaned to form a cleaning system, and flushing with circulating water after the connected cleaning system is subjected to a hydraulic test until effluent is transparent and is free from impurities; B. heating the cleaning system cyclically; C. carrying out alkali wash, and flushing; washing by use of EDTA; and passivating. The process has the following characteristics: energy is saved, the consumption is reduced, the cleaning period is shortened, the cleaning cost is reduced, and the boiler can be cleaned and passivated in one step. After the thermal power plant boiler is cleaned by the EDTA at low temperature, a passivation process is added. An alkali substance is added into EDTA cleanout fluid to regulate the pH value of the EDTA cleanout fluid so as to passivate the cleaned boiler. The cleaning process disclosed by the invention is suitable for boilers of various specifications and is beneficial to implementation and popularization on site.

Description

technical field [0001] The invention relates to a chemical cleaning method for a thermal power plant boiler, in particular to a low-temperature chemical cleaning and passivation process using EDTA. Background technique [0002] According to the requirements of the "Guidelines for Chemical Cleaning of Boilers in Thermal Power Plants", chemical cleaning should be carried out on the boiler body, economizer, and furnace front water supply system for infrastructure and operating units. Chemical cleaning is a necessary measure to prevent accidents caused by corrosion and scaling on the heating surface, and it is also one of the effective measures to improve the thermal efficiency of the boiler and the water vapor quality of the unit. [0003] With the development of the power industry, the continuous commissioning of high-parameter and large-capacity units, and the continuous enhancement of environmental protection awareness, higher and higher requirements are put forward for chem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F22B37/52C23C22/62
CPCC23C22/62C23C22/60F28G9/00C23G1/02C23G1/00C23G1/088
Inventor 陈里宋建华陈兴武陈浩王一波吴兴生孔胜杰张翠文刘娜徐伶
Owner NINGXIA ELECTRIC POWER RES INST
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